On Friday I woke up too early with a splitting headache and chest pain. This was alarming. In the shower, I tried to come up with a list of plausible explanations, but my mind found only one: the four cups of coffee I drank the day before. I wondered, is this how a heart attack begins? For the first time in eight years, I sat down at my desk to work without a mug of jolt.

The rational part of my brain knew why I had jumped to the worst-case scenario. I recently bought a genetic testing kit from 23andMe. After the initial shock about my melanoma risk variants, I calmed down and started digging into the rest of the data. Turns out I carry a variant for a condition that is, in some ways, more unnerving than skin cancer: slow caffeine metabolism.
I should say a word about my coffee habits. I have coffee habits. I live in Brooklyn and buy micro-roasted (in the past three days, if possible) Guatemalan Gorilla from an adorable shop four blocks from my apartment. I grind it myself in small batches and put it immediately into a French press. If you know coffee, you know what all that means. If you don’t know coffee, you’re rolling your eyes but still get my point.

Since I started drinking coffee, in college, I’ve happily ignored the possibility that my ritual is actually an addiction that’s hurting my body and brain. Although some ingredients in coffee — antioxidants, magnesium — are good for us, the one we all know and love, caffeine, might not be. It makes my mind sharper, but it also spurs adrenaline release and raises blood pressure. There’s a huge scientific debate over whether habitual caffeine consumption causes (or prevents!) hypertension, heart attacks and diabetes.

So back to my genes. We metabolize caffeine thanks to a liver enzyme called cytochrome P450 1A2. The enzyme is produced by a gene dubbed CYP1A2.

23andMe found that I carry an ‘C’ variant in CYP1A2 that makes it difficult for the enzyme to do its job. We C people therefore metabolize caffeine more slowly than do people who carry an ‘A’ variant in the same spot. (How much slower? It’s too hard for me figure out, but I think the answer is somewhere in this paper. Or maybe this one. If you can decipher these, please leave a comment and enlighten me!)

A big study from 2006 found that C people under age 60 who drink two to three cups of coffee a day have a 1.87 times higher risk of having a non-fatal heart attack than A people do. C people who drink four or more cups a day (like me) have a 3.47 times higher risk.

These were the numbers swimming through my pounding head on Friday morning as I thought about a life without coffee. It was depressing. It occurred to me that I might be feeling like any other addict who knows, deep down, that a drug is killing me, but is unable or unwilling to give it up. But I also knew that I’m a neurotic worrywart.

A couple of hours later, I left my apartment to go to the dermatologist. It was my first time. Despite my family history of skin cancer, I had never really considered seeing one before getting the 23andMe test results. My doctor was lovely, and after a nice chat and thorough examination of my many, many moles, she gave me a clean bill of skin health and told me to come back in a year. I walked out of the office into pouring rain and barely noticed. My headache and chest pains had vanished. I got home, went straight to the kitchen, turned on the water and took out the French press.

I enjoyed a large cup, but that was it for the day. Everything in moderation, right?

Related

17 thoughts on “My Coffee Problem”

So, I also have 23andme results and we have the same slow-metabolising variant. Now, obviously, the results may be completely inapplicable to me because I belong to a different ethnic group but it says a lot about how people process health information that my first thought was: “Non-fatal, eh? WIN! To the cafetiere!” 😉

I gave up coffee for a year and a half, and there’s no way to sugarcoat how sucky it was. There’s always that perennial question of how much life is worth living without whatever it takes to get you through the day…

your experience fits with my impression of direct-to-consumer genetic testing — it’s useless at best, harmful (at least psychologically) at worst. everyone will have some genetic variants that could increase risk for some condition. there is no good way to handle all that information, to interpret the variants interms of possible disease-causing capability, especially when the literature is inconclusive, as in your case. if you are looking for an answer to a specific question, such as explaining a family history of a specific disease, then targeted genetic testing can be helpful. otherwise, a scan is a scam. since the problem is that a total genetic scan is inherently a form of information overload and difficult to interpret, one can make a case that a whole genome scan ordered by a physician is also something to be avoided.

A small dose of coffee a day keeps the doctor away! It’s a matter of quantity. If you deprive yourself of this little coffee drinking pleasure in life, what else will you cut next… wine, chocolate, strawberries?

i’m really glad the tests have helped you. But my reading of the evidence is that they’re not ready for prime time — we don’t know enough of the risk variants for most traits and diseases yet.

as for difficult-to-interpret phenomena being scientifically useless, i certainly did not intend to imply that. difficult-to-interpet phenomena like blackbody radiation, the hubble redshift and the microwave background radiation have led to extremely important realizations about the composition and history of the universe. however, ordering a gene sequence is not science. it is clinical medicine. and in that context something that can’t clearly be interpreted is not very helpful and may lead to unnecessary and potentially harmful actions. stephen quake started taking a statin as a result of knowing his genome sequence, but there is no evidence that statins are beneficial for a person in his situation and there is a finite risk of muscle damage.

If you are still worried about your consumption, you can at least dampen short-term consequences by taking a detox period, if you can find a two-week patch where no-one will mind too much that you’re crabby and keep yawning. I have to do this every now and then, because my caffeine tolerance is quite low (I wonder about genes now), and the headaches for the first four days are bloody, but after that it’s pretty much life as normal except duller. I guess if you’ve never cleaned out before it might take longer to get off the stocks, but it might still be worth considering.

It’s been two years now since I stopped my caffeine intake cold-turkey. I don’t know what variant I have of the gene. I am very happy without caffeine, I sleep better, and feel more steady throughout the day. The only concessions/changes I’ve consciously made to cope is an understanding that my sleep schedule doesn’t care about the weekend and if I need to get up early the next day, I do my bedtime ritual early so I get to sleep early.

Who We Are

Phenomena is a gathering of spirited science writers who take delight in the new, the strange, the beautiful and awe-inspiring details of our world. Phenomena is hosted by National Geographic magazine, which invites you to join the conversation. Follow on Twitter at @natgeoscience.

Ed Yong is an award-winning British science writer. Not Exactly Rocket Science is his hub for talking about the awe-inspiring, beautiful and quirky world of science to as many people as possible.
Follow @edyong209
Subscribe via RSS